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Aphids, ladybird beetles and Bottle Gourd plant

on 31st May 2019
Bottle Gourd plant – Photo: YC Wee.
Bottle Gourd fruit – Photo: YC Wee.

The Bottle Gourd (Lagenaria siceraria) leaves attract aphids (Superfamily: Aphidoidea) that gather on the undersurface to feed on the plant sap (video below).

Aphids – Photo: DH Murphy.

As these tiny insects suck up the plant sap, excess sap is excreted from the anus as honeydew. The honeydew is sweet and attracts ants that gather around to feed on this liquid. The presence of ants deters predators from the aphid colony (video below). At the same time the pair of tubes (cornicles) sticking out from the back of the aphids also deter predators as they exude defensive chemicals like waxes. As female aphids lay unfertilized eggs, they are very successful as a group

One of the natural enemies of aphids is the ladybird, a beetle, also known as ladybug. The most common ladybird in Singapore is the Transverse Ladybird (Coccinella transversalis) that can grow up to 6mm. It is bright orange to red with black markings across the elytra (Ng et al., 2011). The lifecycle of the ladybird beetle starts with the yellow eggs.

Transverse Ladybird eggs – Photo: YC Wee.

The eggs hatch into larvae.

Transverse Ladybird larva – Photo: YC Wee.

And the larvae develop into pupae.

Transverse Ladybird pupa – Photo: YC Wee.

Finally, the adult ladybirds emerge from the pupae.

Adult Transverse Ladybird – Photo: YC Wee.

The presence of ladybirds indicates a healthy garden. The adult ladybirds as well as their larvae, being carnivorous, feed on aphids and other plants pests, thus keeping the populations of these pests under control.

YC Wee & Dr Leong Tzi Ming
Singapore
21st May 2019

Reference:
Ng, P.K.L., R. Corlett & H.T.W. Tan (eds.) 2011. Singapore Biodiversity: An encyclopedia of the Natural Environment and Sustainable Development. Editions Didier Millet & Raffles Museum of Biodiversity Research, Singapore. p. 356.

If you like this post please tap on the Like button at the left bottom of page. Any views and opinions expressed in this article are solely those of the authors/contributors, and are not endorsed by the Lee Kong Chian Natural History Museum (LKCNHM, NUS) or its affiliated institutions. Readers are encouraged to use their discretion before making any decisions or judgements based on the information presented.

YC Wee

Dr Wee played a significant role as a green advocate in Singapore through his extensive involvement in various organizations and committees: as Secretary and Chairman for the Malayan Nature Society (Singapore Branch), and with the Nature Society (Singapore) as founding President (1978-1995). He has also served in the Nature Reserve Board (1987-1989), Nature Reserves Committee (1990-1996), National Council on the Environment/Singapore Environment Council (1992-1996), Work-Group on Nature Conservation (1992) and Inter-Varsity Council on the Environment (1995-1997). He is Patron of the Singapore Gardening Society and was appointed Honorary Museum Associate of the Lee Kong Chian Natural History Museum (LKCNHM) in 2012. In 2005, Dr Wee started the Bird Ecology Study Group. With more than 6,000 entries, the website has become a valuable resource consulted by students, birdwatchers and researchers locally and internationally. The views and opinions expressed in this article are his own, and do not represent those of LKCNHM, the National University of Singapore or its affiliated institutions.

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